petter ava2-which head?

[beerbellykelly]

hi,i have an old but unused petter twin,it sits on a cross country skid and was a standby for a nurses home,the oil and fuel were original and the timer showed less than 60 hours from new in 1956-it starts and runs beautifully,i am wanting to replace the original 1-phase alternator with a 3 phase unit-i anticipate maximum load to be no higher than 37 amps,although i could get this lower.
im in england.